Face-Sealing Fluidic Connection System

ABSTRACT

A tubing or fitting assembly has an inner tube layer, an outer tube layer, a sleeve, a tip portion, and can have a nut. Each of the nut, sleeve, inner and outer tubing layers, and tip portion have a passageway therethrough, with at least the passageways in the sleeve, tip portion, outer tube layer, and nut adapted to allow the inner tube layer to pass therethrough or extend over the inner layer. The tip portion can be molded over an end portion of the inner tube layer and also over a portion of the sleeve. The sleeve may include a retention feature in the form of a lip which extends into the tip portion, and also a narrower portion so that the tip portion and sleeve remain coupled together. The inner and outer tubing layers can also be retained by an interference fit. The ends of the tip portion and inner layer together define a substantially flat surface which can form a seal in a flat-bottomed port of a component such as may be found in any one of a number of components in an analytical instrument system, including for example a liquid chromatography system. The nut, tube, ferrule, and transfer tube or liner tube may comprise biocompatible materials. In addition, the nut may have a slot, such as a slot adapted to allow the tube and the nut to be easily and quickly separated or to allow a portion of the tube to be easily and quickly inserted in the nut.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation and claims benefit of priority ofU.S. patent application Ser. No. 14/922,041, filed on Oct. 23, 2015,which in turn claims benefit of priority from U.S. Provisional PatentApplication No. 62/067,739, filed Oct. 23, 2014, U.S. Provisional PatentApplication No. 62/127,276, filed Mar. 2, 2015, and U.S. ProvisionalPatent Application No. 62/168,491, filed May 29, 2015, each of which ishereby incorporated by reference herein.

FIELD OF THE INVENTION

The present disclosure relates generally to fitting assemblies andfluidic connection systems, such as those used in connecting componentsof liquid chromatography systems and other analytical instrumentsystems, and, more specifically, to fitting assemblies and fluidicconnection systems for connecting tubing to ports.

BACKGROUND OF THE INVENTION

Liquid chromatography (LC) is a well-known technique for separating theconstituent elements in a given sample. In a conventional LC system, aliquid solvent (referred to as the “mobile phase”) is introduced from areservoir and is pumped through the LC system. The mobile phase exitsthe pump under pressure. The mobile phase then travels via tubing to asample injection valve. As the name suggests, the sample injection valveallows an operator to inject a sample into the LC system, where thesample will be carried along with the mobile phase.

In a conventional LC system, the sample and mobile phase pass throughone or more filters and often a guard column before coming to thecolumn. A typical column usually consists of a piece of steel tubingwhich has been packed with a “packing” material. The “packing” consistsof the particulate material “packed” inside the column. It usuallyconsists of silica- or polymer-based particles, which are oftenchemically bonded with a chemical functionality. The packing material isalso known as the stationary phase. One of the fundamental principles ofseparation is the mobile phase continuously passing through thestationary phase. When the sample is carried through the column (alongwith the mobile phase), the various components (solutes) in the samplemigrate through the packing within the column at different rates (i.e.,there is differential migration of the solutes). In other words, thevarious components in a sample will move through the column at differentrates. Because of the different rates of movement, the componentsgradually separate as they move through the column. Differentialmigration is affected by factors such as the composition of the mobilephase, the composition of the stationary phase (i.e., the material withwhich the column is “packed”), and the temperature at which theseparation takes place. Thus, such factors will influence the separationof the sample's various components.

Once the sample (with its components now separated) leaves the column,it flows with the mobile phase past a detector. The detector detects thepresence of specific molecules or compounds. Two general types ofdetectors are used in LC applications. One type measures a change insome overall physical property of the mobile phase and the sample (suchas their refractive index). The other type measures only some propertyof the sample (such as the absorption of ultraviolet radiation). Inessence, a typical detector in a LC system can measure and provide anoutput in terms of mass per unit of volume (such as grams permilliliter) or mass per unit of time (such as grams per second) of thesample's components. From such an output signal, a “chromatogram” can beprovided; the chromatogram can then be used by an operator to determinethe chemical components present in the sample.

In addition to the above components, a LC system will often includefilters, check valves, a guard column, or the like in order to preventcontamination of the sample or damage to the LC system. For example, aninlet solvent filter may be used to filter out particles from thesolvent (or mobile phase) before it reaches the pump. A guard column isoften placed before the analytical or preparative column; i.e., theprimary column. The purpose of such a guard column is to “guard” theprimary column by absorbing unwanted sample components that mightotherwise bind irreversibly to the analytical or preparative column.

In practice, various components in an LC system may be connected by anoperator to perform a given task. For example, an operator will selectan appropriate mobile phase and column, then connect a supply of theselected mobile phase and a selected column to the LC system beforeoperation. In order to be suitable for high performance liquidchromatography (HPLC) applications, each connection must be able towithstand the typical operating pressures of the HPLC system. If theconnection is too weak, it may leak. Because the types of solvents thatare sometimes used as the mobile phase are often toxic and because it isoften expensive to obtain and/or prepare many samples for use, any suchconnection failure is a serious concern.

It is fairly common for an operator to disconnect a column (or othercomponent) from a LC system and then connect a different column (orother component) in its place after one test has finished and before thenext begins. Given the importance of leak-proof connections, especiallyin HPLC applications, the operator must take time to be sure theconnection is sufficient. Replacing a column (or other component) mayoccur several times in a day. Moreover, the time involved indisconnecting and then connecting a column (or other component) isunproductive because the LC system is not in use and the operator isengaged in plumbing the system instead of preparing samples or othermore productive activities. Hence, the replacement of a column in aconventional LC system involves a great deal of wasted time andinefficiencies.

Given concerns about the need for leak-free connections, conventionalconnections have been made with stainless steel tubing and stainlesssteel end fittings. More recently, however, it has been realized thatthe use of stainless steel components in a LC system have potentialdrawbacks in situations involving biological samples. For example, thecomponents in a sample may attach themselves to the wall of stainlesssteel tubing. This presents problems because the detector's measurements(and thus the chromatogram) of a given sample may not accurately reflectthe sample if some of the sample's components or ions remain in thetubing, and do not pass the detector. Perhaps of even greater concern,however, is the fact that ions from the stainless steel tubing maydetach from the tubing and flow past the detector, thus leading topotentially erroneous results. Additionally, ions can easily bind tobiological compounds of interest, resulting in changes to the moleculesthat affect their retention time in the column. Hence, there is a needfor “biocompatible” connections through the use of a material that ischemically inert with respect to such “biological” samples and themobile phase used with such samples so that ions will not be released bythe tubing and thus contaminate the sample.

In many applications using selector/injector valves to direct fluidflows, and in particular in liquid and gas chromatography, the volume offluids is small. This is particularly true when liquid or gaschromatography is being used as an analytical method as opposed to apreparative method. Such methods often use capillary columns and aregenerally referred to as capillary chromatography. In capillarychromatography, both gas phase and liquid phase, it is often desired tominimize the internal volume of the selector or injector valve. Onereason for this is that a valve having a large volume will contain arelatively large volume of liquid, and when a sample is injected intothe valve the sample will be diluted, decreasing the resolution andsensitivity of the analytical method.

Micro-fluidic analytical processes also involve small sample sizes. Asused herein, sample volumes considered to involve micro-fluidictechniques can range from as low as volumes of only several picolitersor so, up to volumes of several milliliters or so, whereas moretraditional LC techniques, for example, historically often involvedsamples of about one microliter to about 100 milliliters in volume.Thus, the micro-fluidic techniques described herein involve volumes oneor more orders of magnitude smaller in size than traditional LCtechniques. Micro-fluidic techniques can also be expressed as thoseinvolving fluid flow rates of about 0.5 ml/minute or less.

Most conventional HPLC systems include pumps which can generaterelatively high pressures of up to around 5,000 psi to 6,000 psi or so.In many situations, an operator can obtain successful results byoperating a LC system at “low” pressures of anywhere from just a few psior so up to 1,000 psi or so. More often than not, however, an operatorwill find it desirable to operate a LC system at relatively “higher”pressures of over 1,000 psi.

Another, relatively newer liquid chromatography form is Ultra HighPerformance Liquid Chromatography (UHPLC) in which system pressureextends upward to about 1400 bar or 20,000 psi or so, or even more. Inorder to achieve greater chromatographic resolution and higher samplethroughput, the particle size of the stationary phase has becomeextremely small. A stationary phase particle as small as 1 micron iscommon; the resulting high column packing density leads to substantiallyincreased system pressure at the head of the column. Both HPLC and UHPLCare examples of analytical instrumentation that utilize fluid transferat elevated pressures. For example, in U.S. Patent Publication No.2007/0283746 A1, published on Dec. 13, 2007 and titled “Sample InjectorSystem for Liquid Chromatography,” an injection system is described foruse with UHPLC applications, which are said to involve pressures in therange from 20,000 psi to 120,000 psi. In U.S. Pat. No. 7,311,502, issuedon Dec. 25, 2007 to Gerhardt, et al., and titled “Method for Using aHydraulic Amplifier Pump in Ultrahigh Pressure Liquid Chromatography,”the use of a hydraulic amplifier is described for use in UHPLC systemsinvolving pressures in excess of 25,000 psi. In U.S. Patent PublicationNo. 2005/0269264 A1, published on Dec. 8, 2005 and titled“Chromatography System with Gradient Storage and Method for Operatingthe Same,” a system for performing UHPLC is disclosed, with UHPLCdescribed as involving pressures above 5,000 psi (and up to 60,000 psi).Applicants hereby incorporate by reference as if fully set forth hereinU.S. Pat. No. 7,311,502 and US Patent Publications Nos. 2007/0283746 A1and 2005/0269264 A1.

As noted, liquid chromatography (as well as other analytical) systems,including HPLC or UHPLC systems, typically include several components.For example, such a system may include a pump; an injection valve orautosampler for injecting the analyte; a precolumn filter to removeparticulate matter in the analyte solution that might clog the column; apacked bed to retain irreversibly adsorbed chemical material; the HPLCcolumn itself; and a detector that analyzes the carrier fluid as itleaves the column. These various components may typically be connectedby a miniature fluid conduit, or tubing, such as metallic or polymerictubing, usually having an internal diameter of 0.001 to 0.040 inch.

All of these various components and lengths of tubing are typicallyinterconnected by threaded fittings. Fittings for connecting various LCsystem components and lengths of tubing are disclosed in prior patents,for example, U.S. Pat. Nos. 5,525,303; 5,730,943; and 6,095,572, thedisclosures of which are herein all incorporated by reference as iffully set forth herein. Often, a first internally threaded fitting sealsto a first component with a ferrule or similar sealing device. The firstfitting is threadedly connected through multiple turns by hand or by useof a wrench or wrenches to a second fitting having a correspondingexternal fitting, which is in turn sealed to a second component by aferrule or other seal. Disconnecting these fittings for componentreplacement, maintenance, or reconfiguration often requires the use of awrench or wrenches to unthread the fittings. Although a wrench orwrenches may be used, other tools such as pliers or other gripping andholding tools are sometimes used. It will be understood by those skilledin the art that, as used herein, the term “LC system” is intended in itsbroad sense to include all apparatus and components in a system used inconnection with liquid chromatography, whether made of only a few simplecomponents or made of numerous, sophisticated components which arecomputer controlled or the like. Those skilled in the art will alsoappreciate that an LC system is one type of an analytical instrument(AI) system. For example, gas chromatography is similar in many respectsto liquid chromatography, but obviously involves a gas sample to beanalyzed. Such analytical instrument systems include high performance orhigh pressure liquid chromatography systems, an ultra high performanceor ultra high pressure liquid chromatography system, a mass spectrometrysystem, a microflow chromatography system, a nanoflow chromatographysystem, a nano-scale chromatography system, a capillary electrophoresissystem, a reverse-phase gradient chromatography system, or a combinationthereof. Although the following discussion focuses on liquidchromatography, those skilled in the art will appreciate that much ofwhat is said also has application to other types of AI systems andmethods.

Increasing pressure requirements in liquid chromatography havenecessitated the use of high pressure fluidic components. For manyapplications regular stainless steel tubing can be used to withstand thehigh pressure. However, for some types of analyses (e.g., biologicaltesting and metal/ion analysis), stainless steel or other metals are notdesired in the fluid path as the metal could interfere with the testing.Additionally, there are some fields of use (e.g., nano-scale ornano-volume analysis), that require very small inside diameters toaccommodate the extremely low volumes required by these applications.Such small inside diameters are typically not available in stainlesssteel or other high pressure tubing.

In high-performance liquid chromatography (HPLC), ultra high-performanceliquid chromatography (UHPLC), and other high-pressure analyticchemistry applications, various system components and their fluidicconnections must be able to withstand pressures of 15,000 to 20,000 psior so. The types of fluidic connection systems between the tubes thatcarry fluids and the ports that receive fluids in these high-pressureapplications are limited. Many fluidic connection systems rely oncone-shaped, threaded, or welded fittings to attach a tube to areceiving port. These types of connections sometimes may have drawbacks,however. For example, the size of cone-shaped fittings and threadedfittings are dependent on the type and size of any given port, whichmakes quickly interchanging a tube fitted with a particular cone orthreaded fitting between various ports difficult. Othercompression-based fittings have been employed to address this problem.Such fittings often employ a ferrule or a lock ring to help secure oneend of a tube to a receiving port. However, ferrules and lock rings canbecome deformed after multiple uses (e.g., by connecting, disconnecting,and reconnecting to various ports). This is especially true inhigh-pressure applications, where a fluid-tight seal is essential, andwhere a ferrule or lock ring may be more likely to become deformed increating such a seal.

For example, published U.S. Patent Application No. 2013/0043677, titled“Tube and Pipe End Cartridge Seal,” published on Feb. 21, 2013,describes a tube and pipe end cartridge seal for use at high pressures,which relies on a fitting body (including ferrule fittings) toeffectuate a seal with the axial end of a tube. Moreover, a dimple isforged on the annular end of the tube face to further effectuate theseal. Likewise, U.S. Pat. No. 6,056,331, titled “Zero Dead Volume Tubeto Surface Seal,” issued to Bennett et al. on May 2, 2000, describes anapparatus for connecting a tube to a surface using a body, a ferrule,and a threaded fitting. Although Bennett et al. discloses a type of tubeface-sealing apparatus, the apparatus of Bennet et al. relies on athreaded fitting and a ferrule. Similarly, published U.S. PatentApplication No. 2012/0061955, titled “Plug Unite and Connection Systemfor Connecting Capillary Tubes, Especially for High-Performance LiquidChromatography,” published on Mar. 15, 2012, discloses a plug unitconnection system for capillary tubes, wherein a seal is provided at theinterface between a capillary tube and a bushing unit, instead of at thelocation of a ferrule or conical fitting. However, U.S. PatentApplication No. 2012/0061955 relies on the use of a pressure piecesimilar to a ferrule to ensure that enough axial force can be generatedto obtain a seal at the tube face.

Connection assemblies which attempt to effectuate a seal forhigh-pressure applications can require a significant amount of torque toeffectuate a fluid-tight seal, making the creation of such sealsdifficult without the use of additional tools and increasing the risk ofdamage to the fitting assembly or its components due to overtightening.Moreover, experience suggests that many users do not like to use varioustools to connect or disconnect tubing from components such as those invarious AI systems. It is believed that users often apply differentamounts of torque to connect or disconnect tubing and the components insuch systems, thus resulting in potential problems caused byover-tightening or under-tightening (e.g., leakage or loss of sealingwhen the fluid is under pressure).

One example of a flat-bottomed or face-sealing connection assembly isprovided by U.S. Pat. No. 8,696,038, titled “Flat Bottom FittingAssembly” and issued on Apr. 15, 2014 to Nienhuis. Nienhuis teaches atype of flat bottom assembly which includes a flat-sided ferrule, andwherein the assembly including the ferrule and the tube can be pressedagainst a flat bottom port. Another example of a flat-bottomed orface-sealing connection assembly is provided by published U.S. PatentApplication No. 2012/0024411, titled “Biocompatible Tubing for LiquidChromatography Systems,” which was published on Feb. 2, 2012 and wasfiled on behalf of Hahn et al. The Hahn et al. published patentapplication describes tubing having an inner layer and an outer layer,and in which the inner layer can be biocompatible material such aspolyetheretherketone (PEEK) and the outer layer may be a differentmaterial, and in which an end of the tubing may be flared or otherwiseadapted to have a larger outer diameter than other portions of thetubing. The current state of the art for high pressure connections inboth HPLC and UHPLC is to utilize coned ports along with some form offerrule and nut combination with tubing. The nut translates rotationaltorque into axial load that is translated to the ferrule. The loadcauses the ferrule to deform/deflect and grip the tubing, creating aseal. The tube is typically forced into the bottom of the coned port,but there is not currently a mechanism to ensure there is not a gap orspace at the port bottom.

The space at the bottom of the port is a concern for those performingliquid chromatography experiments due to the potential to negativelyinfluence the results with carry over and band broadening. Carry over isjust as it sounds, analyte from one test is carried over to the next.Carry over can produce very unstable results for obvious reasons. Bandbroadening is when the peaks identifying a substance become lesssymmetric and make identification more difficult when peaks of differentmolecules have similar retention times.

One issue with conventional ferrules used with coned ports is that thetorque required to deform/deflect is typically above finger tight levelsin order to achieve UHPLC pressures (e.g., above 12,000 psi or so). Itis desirable to remove tools from the lab by making them unnecessary formaking and breaking fluidic connections and it is advantageous to havefittings that can be connected simply with the fingers rather thantools.

European Patent No. EP 2564104 describes a sealing system for use athigh pressure. End-face seals minimize the sealing radius and thereforeallow various fittings—including known ferrule fittings—to be used inhigh-pressure systems. End-face seals at such high pressure may requiresmooth surfaces, however. In order to reduce cost, an end-facepreparation tool may be required to forge a dimple into the end face tomechanically deform and smooth the surface.

U.S. Pat. No. 6,056,331 describes an apparatus that is composed of threecomponents, a body, a ferrule, and a threaded fitting. The ferrule iscompressed onto a tube and a seal is formed between the tube and adevice retained in the body by threading the fitting into the body whichprovides pressure that seals the face of the ferrule to a mating surfaceon the device. This seal may be used at elevated temperatures, dependingon the materials used. This fitting was developed for use withmicro-machined silicon wafers used in capillary gas chromatography.

U.S. Pat. Nos. 5,525,303, 5,730,943, 6,056,0331, 6,095,572, 6,056,331,7,311,502, 8,696,038, European Patent No. EP2564104, and published U.S.Patent Application Nos. 2005/0269264, 2007/0283746, 2012/0024411,2012/0061955, and 2013/0043677 are hereby incorporated by reference asif fully set forth herein.

SUMMARY OF THE INVENTION

It is therefore an object of the present disclosure to provide a fluidicconnection system useful for high-pressure applications. The system canprovide a sealing connection without the use of additional parts such asferrules, locking rings, or other fittings. It is a further object ofthe present disclosure to provide a fluidic connection system, whereinthe axial force necessary to create an effective seal for high-pressureapplications can be generated manually, with minimal torque and withoutthe use of tools. It is a further object of the present disclosure toprovide a fluidic connection system which is flexible and can be quicklyand easily connected and disconnected with various tubes and portswithout damaging the connection system.

In one embodiment of the present disclosure, a fitting assemblycomprises a nut having a passageway extending therethrough and having afirst end and a second end, wherein said nut has an externally threadedportion near the second end of said nut, a tube having a portionextending through the passageway in said nut, wherein said tubecomprises an inner layer and an outer layer, each having a first end anda second end and each layer having an inside diameter and an outsidediameter, wherein the outer layer of said tube has an inside diametergreater than the outside diameter of the inner layer, and wherein thefirst end of said tube comprises a tip portion, wherein the tip portionhas an inner diameter and an outer diameter and a portion of the innerlayer of said tube is located within the inner diameter of the tipportion, and wherein at least one of a first end of the tip portion andthe first end of the inner layer define a surface adapted to form a sealwith a port, and a sleeve having a passageway therethrough and having afirst end and a second end, with at least a portion of the first end ofsaid sleeve adapted to fit against a surface of said nut and at least aportion of the second end of said sleeve located between the outsidediameter of a portion of the inner layer of said tube and the innerdiameter of the tip portion of said tube, wherein the tip portion ofsaid tube extends over at least a portion of the inner layer of saidtube, at least a portion of the outer layer of said tube, and over atleast a portion of the sleeve. The outer layer of said tube may comprisea first material and the inner layer of said tube may comprise a secondmaterial, and the two materials may be different. The fitting assemblyaccording to claim 2 wherein the first material comprises a materialdifferent than the second material. The sleeve and the outer tube layermay each comprise a metal material, and the inner layer of said tube andthe tip of said tube may comprise a biocompatible material, such aspolyetheretherketone (PEEK). In addition, the sleeve may furthercomprise a retention feature, such as a lip. The tip of the tube may beovermolded over and onto a portion of the inner tube layer.

In another embodiment of the present disclosure, a tubing assembly isprovided, which comprises a tube having an inner layer and an outerlayer, each having a first end and a second end and each having aninside diameter and an outside diameter, wherein said tube furthercomprises a tip portion having a first end, and wherein at least one ofa first end of the inner layer of said tube and the first end of the tipportion of said tube defines a substantially flat surface adapted tocontact and form a seal against a flat-bottomed port, and a sleevehaving a passageway therethrough and having a first end and a secondend, with at least a first portion of said sleeve located between theoutside diameter of a portion of the outer layer of said tube and asecond portion of said sleeve located between the inner diameter of aportion of the tip portion of said tube and the outside diameter of theinner layer of said tube. In such a tubing assembly, the sleeve maycomprise a metal such as stainless steel, the inner layer of said tubemay comprise a biocompatible material such as PEEK, the outer layer ofsaid tube may comprise a material such as stainless steel, and the tipportion of said tube may comprises a biocompatible material, such asPEEK.

In another embodiment, an analytical instrument system is provided whichcomprises at least two components having fluid communicationtherebetween, wherein at least one of said components has aflat-bottomed port having a face, a tube comprising an inner layer andan outer layer, each having a first end and a second end and each havingan inside diameter and an outside diameter, said tube further comprisinga tip portion, wherein a first end of the tip portion of said tubedefines a substantially flat surface, and wherein the tip portion ofsaid tube has a greater outside diameter than the outside diameter ofthe inner layer, a sleeve having a passageway therethrough and having afirst end and a second end, with at least a portion of the first end ofsaid sleeve located between the outside diameter of a portion of theinner layer of said tube and the inner diameter of a portion of the tipportion of said tube, wherein the tip portion of said tube extends overat least a portion of the inner layer and over at least a portion of thesleeve, wherein the first end of the tip portion and the face of theflat-bottomed port are in a sealing engagement, and wherein either orboth of said components comprise any one of the following: pumps,columns, filters, guard columns, injection valves, and other valves,detectors, pressure regulators, reservoirs, degassers, unions, tees,crosses, adapters, splitters, sample loops, and/or connectors. Both theinner layer and the tip portion of said tube may comprise abiocompatible material, such as PEEK.

In another embodiment, a fitting assembly is provided in which a nut hasone or more slots, which can extend the longitudinal length of the nutand which can extend radially from the passageway through the nut to theexterior of the nut. The nut can have one or more such slots, and theslots can extend along only a portion of the longitudinal length of thenut if desired. In addition, the slot can be adapted so that tubing canbe easily inserted into the interior passageway of the nut by anoperator, or can be easily removed from the nut by an operator. The slotis adapted so that a tube or a portion of a tube can be easily insertedinto or removed from the nut through the slot.

Each of the fitting assembly, tubing assembly, and analytical instrumentsystem of the present disclosure are adapted to provide at least onesealing connection for a fluid connection in which the fluid has apressure of between 0 psi and 25,000 psi, between 1,000 psi and 20,000psi, and/or between 2,500 psi and 10,000 psi. Such a sealing connectioncan be made by a user without the use of tools or ferrules, and isadapted so that it can be made with a flat-bottomed port.

These and numerous other features, objects and advantages of the presentdisclosure will become readily apparent to those skilled in the art upona reading of the detailed description, claims and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a conventional liquid chromatographysystem.

FIG. 2 is a detailed cross-sectional view of one embodiment of thefluidic connection system.

FIG. 3 is an cross-sectional view of one embodiment of a fittingassembly of the fluidic connection system.

FIG. 4 is an isometric exterior view of the fitting assembly shown inFIG. 2.

FIG. 5 is a detailed cross-sectional view a portion of the tubing of thefitting assembly in one embodiment.

FIGS. 6A, 6B, and 6C are cross-sectional views of alternativeembodiments of a tubing assembly in accordance with the presentdisclosure.

FIG. 7A is a cross-sectional view of a polymer-lined face sealingconnection with an internal tip.

FIG. 7B is a detailed view of the embodiment of FIG. 7A.

FIG. 7C is a view of a face sealing connection connected with a housingbody.

FIG. 7D is a detailed cross-sectional view of an embodiment of a fittingassembly with an internal tip.

FIG. 8A is a cross-sectional view of a polymer-lined face sealingconnection with an external tip.

FIG. 8B is a detailed view of the embodiment of FIG. 8A.

FIG. 8C is a view of a face sealing connection connected with a housingbody.

FIG. 9A is a cross-sectional view of another embodiment of a polymerlined face sealing connection.

FIG. 9B is a detailed view of the embodiment of FIG. 9B.

FIG. 9C is a view of a face sealing connection connected with a housingbody.

FIG. 10 is an enlarged cross-sectional view of an end of one particularembodiment of an assembly according to the present disclosure.

FIG. 11 is an enlarged cross-sectional view of an end of one particularembodiment of an assembly according to the present disclosure.

FIG. 12 is an enlarged cross-sectional view of an end of one particularembodiment of an assembly according to the present disclosure.

FIG. 13 is an enlarged cross-sectional view of an end of one particularembodiment of an assembly according to the present disclosure.

FIG. 14 is an isometric view of an alternative nut which can be used inembodiments of the present disclosure.

FIG. 15 is a cross-sectional view of the alternative nut of FIG. 10 andcan be used in embodiments of the present disclosure.

FIG. 16 is a second cross-sectional view of the alternative nut of FIGS.10 and 11 and can be used in embodiments of the present disclosure.

DETAILED DESCRIPTION

In FIG. 1, a block diagram of the essential elements of a conventionalliquid chromatography (LC) system is provided. A reservoir 101 containsa solvent or mobile phase 102. Tubing 103 connects the mobile phase 102in the reservoir 101 to a pump 105. The pump 105 is connected to asample injection valve 110 which, in turn, is connected via tubing to afirst end of a guard column (not shown). The second end of the guardcolumn (not shown) is in turn connected to the first end of a primarycolumn 115. The second end of the primary column 115 is then connectedvia tubing to a detector 117. After passing through the detector 117,the mobile phase 102 and the sample injected via injection valve 110 areexpended into a second reservoir 118, which contains the chemical waste119. As noted above, the sample injection valve 110 is used to inject asample of a material to be studied into the LC system. The mobile phase102 flows through the tubing 103 which is used to connect the variouselements of the LC system together.

When the sample is injected via sample injection valve 110 in the LCsystem, the sample is carried by the mobile phase through the tubinginto the column 115. As is well known in the art, the column 115contains a packing material which acts to separate the constituentelements of the sample. After exiting the column 115, the sample (asseparated via the column 115) then is carried to and enters a detector117, which detects the presence or absence of various chemicals. Theinformation obtained by the detector 117 can then be stored and used byan operator of the LC system to determine the constituent elements ofthe sample injected into the LC system. Those skilled in the art willappreciate that FIG. 1 and the foregoing discussion provide only a briefoverview of a simplistic LC system that is conventional and well knownin the art, as is shown and described in U.S. Pat. No. 5,472,598, issuedDec. 5, 1995 to Schick, which is hereby incorporated by reference as iffully set forth herein. Those skilled in the art will also appreciatethat while the discussion herein focuses on a LC system, otheranalytical systems can be used in connection with various embodiments ofthe invention, such as a mass spectrometry, microflow chromatography,nanoflow chromatography, nano-scale liquid chromatography, capillaryelectrophoresis, or reverse-phase gradient chromatography system.

Preferably, for an LC system to be biocompatible, the various components(except where otherwise noted) that may come into contact with theeffluent or sample to be analyzed are made of the synthetic polymerpolyetheretherketone, which is commercially available under thetrademark “PEEK” from Victrex. The polymer PEEK has the advantage ofproviding a high degree of chemical inertness and thereforebiocompatibility; it is chemically inert to most of the common solventsused in LC applications, such as acetone, acetonitrile, and methanol (toname a few). PEEK also can be machined by standard machining techniquesto provide smooth surfaces. Those skilled in the art will appreciatethat other polymers may be desirable in certain applications.

Referring now to FIG. 2, a detailed cross-sectional view of oneembodiment of a fitting assembly for a fluidic connection system 1 isshown. Fluidic connection system 1 includes an actuator nut 2. Actuatornut 2 includes a first portion 6 proximate to the end 5 of the head ofnut 2, and a non-tapered portion 8 proximate to the first portion 6. Theactuator nut 2 also includes an externally threaded portion 9 havingthreads in a shape which corresponds to the shape of a first internallythreaded portion 22 of a housing body 21. As shown in FIG. 2, housingbody 21 comprises a union, but those skilled in the art will appreciatethat instead of a union, the housing body 21 could be any one of a widevariety of components in an LC, HPLC, UHPLC, or other AI system,including for example, any of the following: pumps, columns, filters,guard columns, injection valves and other valves, detectors, pressureregulators, reservoirs, and other fittings, such as unions, tees,crosses, adapters, splitters, sample loops, connectors, and the like.

As shown in FIG. 2, said externally threaded portion 9 of said actuatornut 2 is rotatably engaged with the internally threaded portion 22 ofsaid housing body 21, thereby removably connecting said nut 2 to thehousing body 21. The rotatable engagement of said externally threadedportion 9 of said nut 2 with the internally threaded portion 22 of saidhousing body 21 removably secures said actuator nut 2 to said housingbody 21. (By turning the head portion of nut 2 in the oppositedirection, a user can also disconnect the nut 2 from the housing body21.) When connected (as shown in FIG. 2), axial force on the tube endface 15 is provided when the actuator nut 2 is rotated. As shown in FIG.2, the rotation of nut 2 relative to body 21 results in the externallythreaded portion of nut 2 extending further into the port of body 21,until the port end face 35 and tube end face 15 touch. The force exertedon the tube end face 15 by rotating said actuator nut 2 forms a seal atthe interface of the tube end face 15 and the port end face 35.

Tube end face 15 is defined by an end face of an inner tube layer 13 andan end face of an outer tube tip 14. The outer tip 14, sometimesreferred to herein as the tube tip 14 or as tip 14, has a first end 30and a second end 31, with said tube end face 15 being proximate to thefirst end 30. Between said first end 30 and said second end 31, tube tip14 surrounds an inner layer 13 of the tube. In one embodiment, tube tip14 is secured to a sleeve 12 of the tubing assembly by a retainerfeature 16, which can be a feature or combination of features of asleeve 12. Proximate to the second end 31 of said overmolded tube tip14, a sleeve 12 surrounds the inner tubing layer 13. In one embodiment,sleeve 12 surrounds said inner tubing layer 13 between the second end 31of said tube tip 14 and the first end 3 of said actuator nut 2. As shownin FIG. 2, sleeve 12 and inner tubing layer 13 extend and pass through apassageway through the axial length of the actuator nut 2, between theexternally threaded portion 9 by means of a passageway 11.

The use of an internally threaded portion 22 on said housing body 21 isa matter of choice. Those skilled in the art will therefore appreciatethat, in an alternative embodiment, the nut 2 could have an internallythreaded portion (not shown) and the housing body 21 could have anexternally threaded portion (not shown).

Although not shown in FIG. 2, the tubing inner layer 13 preferably hasan outer layer surrounding at least a portion thereof. Referring now toFIG. 3, a tubing outer layer 19 can be seen. As shown in FIG. 3, theouter layer 19 is located outside and around the inner tubing layer 13.In addition, a portion of the outer tubing layer 19 is located insidethe sleeve 12, and an end portion of the outer tubing layer 19 extendsbeyond an end of the sleeve 12 and is located inside the overmolded tubetip 14. As also shown in FIG. 3, a portion of the inner layer 13 extendsbeyond the end of the outer layer 19 in this embodiment. In oneparticular embodiment, the sleeve 12 and outer tubing layer 19 can besecured to each other, such as by welding, adhesives, or by resinepoxies or other plastics, which can be located between the outsidediameter of the outer layer 13 and the inner diameter of the sleeve 12.Securing the outer tubing layer 19 and the sleeve 12 helps preventrotation of either independent of the other.

It will be appreciated that the tubing layer 13 can comprise a number ofdifferent materials depending on the particular application, as that mayinvolve a particular type of sample, a particular type of solvent,and/or a particular pressure range. For example, the outer layer 19 oftube can comprise a metal, such as stainless steel (such as 316stainless steel) or titanium, or a reinforced polymeric material,including composite or braided materials, such as polymeric materialsthat are reinforced or braided with carbon, carbon fibers, steel fibers,or the like. In embodiments comprising a metallic outer layer 19, themetal temper can be varied to provide a balance between high pressurecapability and tubing flexibility. The inner layer 13 can comprise abiocompatible polymer, such as polyetheretherketone (PEEK). Otherpolymer materials which may be used for the inner layer 13 include, butare not limited to, TEFLON®, TEFZEL®, DELRIN®, perfluoroalkoxy (PFA,also called perfluoroalkoxyethylene), fluorinated ethylene propylene(PEP), polytetrafluoroethylene (PETE), ETFE (a polymer oftetrafluoroethylene and ethylene), polyetherimide (PEI), polyphenylenesulfide (PPS), polypropylene, sulfone polymers, polyolefins, polyimides,other polyaryletherketones, other fluoropolymers, polyoxymethylene(POM), and others, depending on the foregoing factors or perhaps others.In addition, PEEK (or other polymers) may be used that is reinforced orbraided with carbon, carbon fibers, steel fibers, or the like.Furthermore, in certain embodiments the inner layer 13 may be coatedwith a material to increase strength, improve chemical resistance,improve temperature stability, or reduce permeability. Such coatingsinclude, but are not limited to, metallization, polymeric coating,silicon-based coatings, and carbon-based coatings. Additionally, incertain embodiments the inner layer may be heat treated to improveproperties such as crystallinity, chemical resistance, or permeability.Those skilled in the art will appreciate that, although shown anddescribed herein as a single layer, the inner layer 13 of the tube mayactually comprise two or more layers if desired. The final tube may betreated to further improve the performance, including heat treatment orannealing to strengthen the polymer components, or pressurizing, with orwithout added heat, to allow the inner layer to conform to the outerlayer. A mandrel can be used in the inner diameter of the inner layer topreserve the passageway.

Actuator nut 2, inner tubing layer 13, sleeve 12, and retainer feature16 may be embodied in a variety of configurations. Turning now to FIG.3, overmolded tube tip 14 is secured to the sleeve 12 by retainerfeature 16. The same numerals are used throughout the Figures asappropriate to identify the same features for convenient reference. Asshown in FIG. 3, the retainer feature 16 has a protrusion which extendsaway from the inner layer 13 of the tube and towards the outer diameterof outer layer 14. The retainer feature 16 extends into a portion of theovermolded tube tip 14. Retainer feature 16 prevents the overmolded tubetip 14 from disengaging from the sleeve 12 and inner tubing layer 13.Retainer feature 16 also helps prevent the overmolded tube tip 14 fromslipping while radial torque is being applied to the actuator nut 2 andaxial force is being applied to the tube end face 15. Those skilled inthe art will also appreciate that the retainer feature 16 may be ofdifferent configurations. For example, more than one retainer feature 16may be used (not shown). Alternatively, the retainer feature 16 may beof a different shape or size than suggested by FIG. 3. Alternatively,the retainer feature 16 may be substituted by alternate means ofsecuring the overmolded tube tip 14 to the sleeve 12, such as by meansof an adhesive or by means of welding the overmolded tube tip 14 to thesleeve 12.

Referring now to FIG. 4, another view of the fitting assembly is shown.As shown in FIG. 4, actuator nut 2 preferably has a circular shape, andthe exterior surface of the head portion of said actuator nut 2 has aplurality of splines 7 spaced around the head of the nut 2. While thoseskilled in the art will appreciate the advantages of a circular-shapedactuator nut 2, those skilled in the art will also appreciate that theactuator nut 2, and/or the head of the nut 2, may have a non-circularshape, such as a box shape (not shown), a hexagonal shape (not shown),or other shapes. In addition, those skilled in the art will appreciatethat the exterior surface of the actuator nut 2 may be flat (not shown)or cross-hatched (not shown), instead of characterized by splines 7. Avariety of actuator nut 2 shapes and exterior surfaces may be used suchthat said actuator nut 2 may be easily gripped and manually rotated byan operator.

As shown in FIG. 4, the sleeve 12, inner tubing layer 13, and outertubing layer 19 can be adapted to fit at least partially into apassageway 11. Inner and outer tubing 13 and 19, respectively, exit theactuator nut 2 through a hole (not shown) in the head 5 of the nut 2proximate to the first end 3 of the actuator nut 2. Inner tubing layer13 is preferably comprised of a biocompatible material such as syntheticpolymer polyetheretherketone, which is commercially available under thetrademark PEEK™ from VICTREX®. The outer layer 19 is preferably metal,such as stainless steel. Overmolded tube tip 14 can also comprise PEEK™in this particular embodiment. Those skilled in the art will appreciatethat inner tubing layer 13 and said overmolded tube tip 14 may becomprised of other polymer materials, including for example TEFLON®,TEFZEL®, DELRIN®, perfluoroalkoxyethylene (PFA), polytetrafluoroethylene(PETE), polyetherimide (PEI), polyphenylene sulfide (PPS),polypropylene, polyolefins, polyimides, or polyoxymethylene (POM).Either or both Inner tubing layer 13 and overmolded tube tip 14 mayalternatively be comprised of carbon-fiber or steel-fiber materials thatare interwoven with polymer materials, such as carbon-fiber PEEK™.Either or both inner tubing layer 13 and overmolded tube tip layer 14may alternatively be comprised of a nano-composite material.

In one embodiment, actuator nut 2 is comprised of a metal, such as, forexample, stainless steel. Those skilled in the art will appreciate thatthe actuator nut 2 may be comprised of other materials such as titanium,fused silica, or a reinforced rigid polymer material (e.g., acarbon-fiber PEEK™ or other metal-braided polymer material). More rigidpolymer materials may be more desirable in some applications, sincestainless steel has some drawbacks in biological environments. Forexample, components in a biological fluid can attach to stainless steel,and stainless steel ions may leak into said fluid—both events having thepotential to obscure measurements in liquid chromatography and otheranalytic chemistry applications.

FIG. 5 provides an enlarged view of the cross-section of the combinationof the inner layer 13 of the tube, the outer layer 19 of the tubing, andthe sleeve 12. In this embodiment, a passageway 24 extends along thelongitudinal axis of the inner tubing layer 13 (and also outer tubinglayer 19). A fluid or gas may be run through said passageway 24. In thisembodiment, the tube has an end face or surface 15 which issubstantially flat. However, those skilled in the art will appreciatethe tube end face 15 may have other shapes, such as a rounded or dimpledsurface (not shown). A flat or substantially flat surface 15 is believedto be sufficient for purposes of creating an effective seal with theport end face 26, but other shapes or configurations of end face 15 maybe used so long as the surfaces of the tube end face 15 and the port endface 35 are adapted to form a seal when engaged with one another. Othersuch embodiments are discussed below in connection with FIGS. 6A, 6B,and 6C. In one embodiment, sleeve 12 is comprised of a metal, such as,for example, stainless steel. Those skilled in the art will appreciatethat the sleeve 12 and/or outer tubing layer 19 may be comprised ofsteel or other materials such as titanium, fused silica, or areinforced, rigid polymer material (e.g., carbon-fiber PEEK™,steel-braided TEFLON®). Particularly, rigid polymer materials may bemore desirable in some applications, since stainless steel has somedrawbacks in biological environments, as is described above.

Still referring to FIG. 5, additional features of the tubing assemblyare shown in an enlarged cross-section view. Retention features 16 and17, for example, are shown in more detail. As shown in FIG. 5, theretention feature 16 is a portion of sleeve 12 and is located at the endof the sleeve 12 which is closest to the face 15 defined by the end ofthe inner tube layer 13 and outer tube layer 14. Retention feature 16 isa protrusion or extension of sleeve 12 that provides a lip at the end ofsleeve 12. As shown in FIG. 5, the outward edge of the lip 16 is locatedfurther from the longitudinal axis of the inner layer 13 than anadjacent portion 17 of the sleeve 12. The combination of features 16 and17 help hold the outer layer 14 once attached to sleeve 12 and thus keepthe combination of inner layer 13, outer layer 14, and sleeve 12 frombeing detached from one another.

Also shown in FIG. 5 is a recessed portion 40 of the sleeve 12 at theend opposite the location of the retention features 16 and 17. Therecessed portion 40 can be a conically-shaped or parabollicaly shapedrecess, such that the end of sleeve 12 with the recessed portionprovides an opening with a diameter greater than that of the passagewaythrough the sleeve 12. The recessed portion 40 thus makes it easier toinsert an end of the combined inner layer 13 and outer layer 19 into thepassageway through the sleeve 12 for easier and faster manufacturing ofthe tubing assembly comprising inner layer 13, outer layer 19, and thesleeve 12. In addition, the recessed portion 40 provides moreflexibility to the tubing assembly once manufactured, because a user canmore easily bend the portion of the inner layer 13 that extends out ofthe passageway of the sleeve 12 at the end opposite the end of theassembly at which surface 15 is located. As noted above, sleeve 12 andouter layer 19 can be secured together. In one embodiment, sleeve 12comprises a metal (such as stainless steel), outer tubing layer 19comprises a metal (such as stainless steel), and sleeve 12 and outerlayer 19 are secured together by welding (or by crimping or swaging) ator near portion 40 of sleeve 12.

The tube tip 14 can be overmolded onto an end portion of the innertubing layer 13, the outer tubing layer 19, and sleeve 12. For example,and as shown in FIG. 5, the inner tube 13 and outer tube 19 may beinserted through the passageway extending through the sleeve 12 so thatthe first ends of both the inner tube layer 13 and outer tube layer 19extend a predetermined distance from the first end of the sleeve 12. Thecombination of the inner tube 13, outer tubing 19, and the sleeve 12 inthis configuration can then have the outer tip 14 overmolded onto thecombination, thereby forming the portion of the tubing assembly whichcomprises the inner layer 13 of the tube, the outer layer 19 of thetube, the sleeve 12, and overmolded tube tip 14. In one process formaking this combination, the tube tip 14 is molded onto and over theinner layer 13, the outer layer 19, and the sleeve 12 by the process ofinjection molding. Those skilled in the art will appreciate that otherprocesses may be used, such as casting and welding, and may be selecteddepending on the materials selected for the inner layer 13, the outerlayer 19, and the tube tip 14. If desired, the surface 15 of the firstend of the tubing as defined by the combination of the end of the innerlayer 13 and the end of the tube tip 14 may be further finished, such asby cutting the first end of the tubing, polishing the first end of thetubing, or machining, with such processes performed to obtain asubstantially flat surface 15 defined by the first ends of the innerlayer 13 and the tube tip 14.

Referring now to FIGS. 6A, 6B, and 6C, alternative embodiments of atubing assembly in accordance with the present disclosure are shown.Like numerals are used for the tip 14, inner tubing layer 13, sleeve 12,and outer tubing layer 19 in FIGS. 6A, 6B, and 6C for ease of reference.In FIG. 6A, a tubing assembly 60 is shown. The tubing assembly 60includes an inner tubing layer 13, and outer tubing layer 19, a sleeve12, and also a tubing tip 14. However, the tubing tip 14 in FIG. 6A hasportions 14 a and 14 b which are angled from the outer diameter of thetip 14 towards the longitudinal axis of the tubing assembly 60. Thisconfiguration reduces the surface area of the surface 15 defined by theends of the inner layer 13 and the tip 14 which is adapted to contact aface in a flat-bottomed port. It is believed that by reducing thesurface area of the seal, we also are able to reduce the force requiredto obtain a seal.

Referring to FIG. 6B, a tubing assembly 61 includes an inner tubinglayer 13, a sleeve 12, an outer tubing layer 19, and also a tip 14. Asshown in FIG. 6B, the end of the inner tubing layer 13 is not flush withthe end of the tip 14, thus leaving a gap 14 c defined by the innerdiameter of the tip 14. In the tubing assembly 61 of FIG. 6B, thesurface 15 at one end of the tubing assembly 61 that is adapted tocontact a surface in a flat-bottomed port is defined by the surface atthe end of the tip 14 and not the end of the inner tubing layer 13. Thisconfiguration also reduces the surface area of the tubing assembly whichis adapted to contact and seal with a flat-bottomed port.

Referring now to FIG. 6C, another embodiment is shown. In FIG. 6C, thetubing assembly 62 includes an inner tubing layer 13, a sleeve 12, anouter tubing layer 19, and a tip portion 14. The end of the tip portion14 has portions 14 d and 14 e which include a “stepped” shape in whichan outer portion extends towards the longitudinal axis of the tubingassembly 62 and then an angled portion extends from the step portiontowards the end of the tip 14 and towards the longitudinal axis of thetubing assembly 62. This embodiment also helps reduce the surface areaof the surface 15 defined by the combination of the end of the innertubing layer 13 and the inner portion of the end of the tip 14 definedby the stepped end portions 14 d and 14 e.

Those skilled in the art will appreciate that other configurationsbesides those illustrated and described in this disclosure can be usedin various applications of the tubing and fitting assemblies inaccordance with the present disclosure. It will also be appreciated thatthe materials described above which can be used for the various featuresand components of the fitting and tubing assemblies of the presentdisclosure can likewise be used for the same or similar features andcomponents of the tubing assemblies illustrated in FIGS. 6A, 6B, and 6C.

A further embodiment is shown in FIGS. 7A-C. The embodiment 70 of FIG.7A also includes an actuator nut 70, comprising a head portion 71 at afirst end thereof and a threaded portion 76 near a second end thereof,wherein the an external threaded portion 76 is configured to interactwith an internally threaded connection 22, in a housing 21, best shownin FIG. 7C. The nut defines a passageway therethrough sized and shapedto contain a liner tubing 75 and a reinforcement tubing 74, wherein theliner tubing 75 can be concentrically contained with the reinforcementtubing 74. A portion of the passageway proximate and at least partiallycontained with the externally threaded portion 76 is also sized tocontain a transfer tubing 72. In the embodiment shown in FIG. 7C, thereinforcement tubing 74, the liner tubing 75 and the transfer tubing 72extend out of the passageway through the second end of the nut 71 andterminate at tube end face 78. The transfer tubing 72 can be secured tothe reinforcement tubing 74 by swaging or crimping onto the tubing withmechanical force radially or by any appropriate means known to thoseskilled in the art that allows for axial forces resulting from the fluidpressure reacted through the transfer tubing 72 and reinforcement tubing74, such as welding, for example. This configuration (shown in FIG. 7D)allows the tip 73 to be compressed between the reinforcement tubing 74and a port bottom, which aids in creating a fluidic seal and preventsdead volume. The liner tubing 75 can be secured in the reinforcementtubing by an interference fit formed by feeding liner tubing 75 with anouter diameter greater than the internal diameter of reinforcementtubing 72 through the reinforcement tubing 72, thereby providing a tightinterference fit, or such as by feeding liner tubing 75 throughreinforcement tubing 75 and then either increasing the outer diameter ofthe liner tubing 75 or decreasing the inner diameter of thereinforcement tubing 72, or by other means known to those skilled in theart.

As further shown in FIG. 7A, the device further comprises a tip 73. Asshown, the reinforcement tubing 74, the liner tubing 75 and the transfertubing 72 extend out the second end of the nut 71 and terminate in atube end face 78, in proximity to each other at a distance from thesecond end of the nut, configured to extend into a housing 21 throughand past an internally threaded portion as described above. The tip 73is disposed at the terminal end and is positioned to contact a face of aport extended into the housing 21 as shown in FIG. 7C.

During use, the nut 71 is reversibly connected to the housing bythreading the external threads into a housing and reversibly connectinga port to the opposite end of the housing, a face seal is establishedbetween the tip and the bottom of the port without the use of ferrulesto grip the tubing. The fitting assembly nut 71 drives against thebearing surface of the transfer tubing 72 to push the sealing surface ofthe tip 73 into and against the port bottom. The tip seal to the linertubing 75 is created by an interference fit created by the internaldiameter of the tip being smaller than the outside diameter of thetubing that requires the liner tubing 75 to be drawn into the tip 73.The tip 73 can be slid into position against the reinforcement tubing74. The transfer tubing 72 is slid over the outside of the tip 73 andcrimped into place by means known to those skilled in the art including,for example, the presence of angled surfaces that interact to create ataper lock interference fit. In the embodiment described and shown inFIGS. 7A-C, there are not any angles on the tip 73, transfer tubing 72,reinforcement tubing 74, or liner tubing 75. The assembly instead usesthe interference between the components to retain the integrity of theseal and connection system. The reinforcement tubing 74 and transfertubing 72 can be metal, selected from but not limited to stainlesssteel, steel, or titanium. The tip 73 and liner tubing 75 can be made ofsofter materials, including polymers such as PEEK, carbon filled PAEK,PEEK, PEKK, FEP, PFA, ETFE, or PTFE, for example. The nut 71 cancomprise either one or more metals such as stainless steel, aluminum,titanium, or nickel, for example, or one or more polymers as appropriatefor the intended use in particular systems, and with particular fluids.

A closer view of the fitting including the tubing and passageway isshown in FIG. 7B. As can be seen in the figure, the liner tubing andreinforcement tubing are drawn into the interior diameter of the tip toprovide an interference fit. The transfer tubing can then be slid overthe outside of the tip and in place, or held in place by otherappropriate methods known in the art. The fitting is shown as itinteracts with a housing body 21 for connection to a port. As shown inthe figure, the tubing end face 78 extends through the threaded portion76 and into the housing body past the mated threaded portions 76 and 22.The terminal end face can thus be pressed against a port end face tocreate a seal.

An alternate embodiment of the fitting of FIG. 7A-C is shown in FIG. 7D.As shown in the figures, the second end of the transfer tubing 72includes an angled internal face portion 77 and the tip 73 includes anoppositely angled outer face portion 79 to facilitate easier insertionof the tip 73 into the transfer tubing 72 by a user.

An embodiment including an alternate tip 83 is shown in FIGS. 8A-C. Inthis embodiment, all common items are numbered the same as in theembodiment shown in FIGS. 7A-C. The tip 83 shown in FIGS. 8A-C, however,is no longer captured by the transfer tubing 72 with an interferencefit. This embodiment instead uses the transfer tubing 72 to driveagainst the tip 83 during assembly to create a face seal on a sealingsurface in a port and the surfaces contacting the transfer tubing 72.The tip 83 is drawn onto the tubing and utilizes an interference fit tocreate a seal between the liner tubing 75 and tip 83. All of thecomponents of the embodiment of FIGS. 8A-C can be manufactured from thesame materials as the embodiment shown in FIGS. 7A-C.

An enlarged view of the embodiment of FIG. 8A is shown in FIG. 8B. Inthis view it is shown that the transfer tubing 72 is shortened from thetube face end 78 such that the tip abuts the terminal end of thetransfer tube 72, while the liner tube 74 and reinforcement tube 75 arecontained in the inner diameter of the tip 83. A view of a fitting asdescribed in FIG. 8A connected to a housing body 21 is shown in FIG. 8C.As describe above, when the nut is driven into the housing, the tip 83at the tube face 78 is forced against a port face by the transfer tubing72 to create a face seal.

Another embodiment of a connection assembly is shown in FIGS. 9A-C. Thisembodiment does not include a liner tubing. The embodiment uses thesealing of the tip 93 in a port bottom along with sealing of the tip 93to a conduit tubing 94. The transfer tubing 92 translates the load fromthe rotational torque of the nut when applied by an operator to bothsealing areas of the tip 93. The transfer tubing 92 in this embodimentcan be made of a more durable or less resilient material such as a metalmaterial, with stainless steel being an exemplary material, and thetransfer tubing includes a pocket portion 96. There is interferencebetween the outside diameter of the tip 93 and the pocket portion 96 inthe transfer tubing 92. The interference is effective to retain the tip93 on the conduit tubing 94 during assembly and disassembly. Inaddition, the face of the tip is effective to form a seal with a portsealing face as shown in FIG. 9C. The use of a stainless steel transfertubing 92 allows for the use of higher pressures. Pressures in excess of15,000, 20,000, and 25,000 psi have been achieved in test samples ofthis embodiment without leaking. The conduit tubing 94 and transfertubing 92 can be manufactured from and comprise stainless steel tubing,for example, or can be made from other metals as known to those skilledin the art. The tip 93 can include one or more polymers such as PEEK,carbon fiber reinforced PEEK, PEKK, FEP, PFA, ETFE, or PTFE, forexample. The fitting can be either a metal such as stainless steel,aluminum, or titanium, for example, or one or more polymers depending onsystem requirements. An enlarged view of the tubing as shown in FIG. 9Ais shown in FIG. 9B, in which the tip 93 can be seen extending into thepocket portion 96 effective to be held against the conduit tubing 94 andforming a tube face end effective to form a face seal with a port sealface as shown in FIG. 9C.

Additional embodiments of the disclosed connection assemblies that canbe used to form a face seal with various flat bottomed ports or fixturesas required and that do not include a liner tubing are shown in FIGS.10-13. The connector assembly shown in FIG. 10 includes a transfertubing 92 surrounding the conduit tubing 94 as in the embodiment shownin FIG. 9A. There is again interference in this embodiment between theoutside diameter of the tip 93 and the pocket portion 96 and thetransfer tubing 92. It can be seen in this embodiment that the end face98 of the transfer tube is flush with the end face 99 of the conduittubing 94.

An additional embodiment is shown in FIG. 11 in which the end face 99 ofthe conduit tubing 94 extends beyond the end face 98 of the transfertubing 92. The pocket portion 96 and the tip in this embodiment extendfrom the inner diameter to the outer diameter of the conduit tubing 94and is not disposed between the end of the conduit tubing and the port(not shown). A further embodiment is shown in FIG. 12 in which the endface 99 of the conduit tubing 94 extends even further out of thetransfer tubing 92. Such connection assemblies are shown to indicatethat the disclosed embodiments can be altered or configured toeffectively seal with a variety of connectors or ports as needed, or toprovide an effective seal at various pressures and volumes.

As described for FIG. 9, the embodiments shown in FIGS. 10-12 do notinclude a liner tubing. The embodiments use the sealing of the tip 93 ina port bottom along with sealing of the tip 93 to a conduit tubing 94.The transfer tubing 92 translates the load from the rotational torque ofthe nut when applied by an operator to both sealing areas of the tip 93.The transfer tubing 92 in these embodiments can be made of a moredurable or less resilient material such as a metal material, withstainless steel being an exemplary material, and the transfer tubingincludes a pocket portion 96. There is interference between the outsidediameter of the tip 93 and the pocket portion 96 in the transfer tubing92. The interference is effective to retain the tip 93 on the conduittubing 94 during assembly and disassembly. In addition, the face of thetip is effective to form a seal with a port sealing face. The use of astainless steel transfer tubing 92 allows for the use of higherpressures. The conduit tubing 94 and transfer tubing 92 can bemanufactured from and comprise stainless steel tubing, for example, orcan be made from other metals as known to those skilled in the art. Thetip 93 can include one or more polymers such as PEEK, carbon fiberreinforced PEEK, PEKK, FEP, PFA, ETFE, PEEKsil, or PTFE, for example.Alternatively, the conduit tubing 94 can be a capillary tube, such as acapillary made of silica, fused glass, PEEKsil (fused silica with asheath of polyetheretherketone), the transfer tubing 94 can be made of apolymer such as one or more of those noted above, and/or the tip 93 canbe made of metal, such as stainless steel. The fitting can be either ametal such as stainless steel, aluminum, or titanium, for example, orone or more polymers depending on system requirements.

Referring now to FIG. 13, yet another alternative embodiment of thepresent disclosure is provided. FIG. 13 is an enlarged cross-sectionalview of an end of the assembly. In FIG. 13, an assembly is shown whichincludes conduit tubing 94, transfer tubing 92, and a tip 93. Inaddition, the assembly includes a sleeve 97. As shown in FIG. 13, thesleeve 97 includes pockets 96 in which a portion of the tip 93 islocated. In this particular embodiment, the end face 99 of conduittubing 94 is flush with an end face of the tip 93, and the end faces oftip 93 and conduit tubing 94 are adapted to abut a port (not shown inFIG. 13). As also shown in FIG. 13, in this particular embodiment, anend face 95 of the sleeve 97 is flush with the end face 98 of thetransfer tubing 92. Those skilled in the art will appreciate that thetransfer tubing 92, conduit tubing 94, sleeve 97, and tip 93 can each bemade of various materials, including those noted above for theembodiments shown in FIGS. 10-12, including polymeric, metal, andceramic materials, and may be varied depending on the intendedapplication of the assembly, such as the pressures involved, thesolvents and fluids involved, and the like.

In FIG. 14, an alternative nut 1001 is shown. The nut 1001 can be usedin any of the foregoing embodiments. As shown in FIG. 10, the nut 1001has a first end portion 1005, as well as an externally threaded portion1010, a lower portion 1015, a knurled portion 1020, and a top portion1025 at the second end of the nut 1001. The nut 1001 has openings 1026and 1028 at its top and bottom (or second and first) ends, respectively.The openings 1026 and 1028 are open to a passageway 1030 (shown in FIGS.15 and 16) extending longitudinally through the nut 1001. The nut 1001also has a slotted, grooved or split portion 1050. As shown in FIG. 10,the slot or groove 1050 extends the longitudinal length of the nut 1001.Radially, the groove 1050 also extends from the outer surface of the nut1001 to the passageway 1030 (not shown in FIG. 14) extending along thelongitudinal axis of the nut 1001.

The groove or slot 1050 of the nut 1001 provides an advantage because itallows an operator to route a tube (such as described above in variousembodiments) through an analytical instrument system and/or its variouscomponents, then add the nut 1001 to make up a connection with thefitting assembly after the tube is roughly in place. In a number ofapplications, the space for the various components can be limited andfairly tight, and in such situations having the nut captivated on thetube assembly can make it difficult to route the assembly to the properlocation to make up a connection. Because tubes periodically need to bereplaced in AI systems, having the slot 1050 on the nut 1001 allows foreasier location and for easier and faster replacement of tubing in manysituations. This approach also makes it easier and more common for reuseof the nut 1001, since the nut 1001 need not be attached to the tubing.The groove 1050 also may allow for easier use of the nut 1001 when thenut 1001 is rotated in engagement with a port, such as a port in an LC,HPLC, UHPLC, or other AI system, or other component, such as in such asystem (which could be a union, pump, column, filter, guard column,injection valve or other valve, detector, pressure regulator, reservoir,or another fitting, such as a tee, cross, adapter, splitter, sampleloop, connector, or the like) to make a fluidic connection, such as whenused in connection with the embodiments of this disclosure describedabove. Those skilled in the art will appreciate that, in an alternativeembodiment, the nut 1001 could have an internally threaded portion (notshown) adapted to engage with an externally threaded portion of a portor other component such as those listed, or could be otherwiseconfigured to provide axial loading.

The nut 1001 can be made of a metal, such as, for example, stainlesssteel. Those skilled in the art will appreciate that the nut 1001 may becomprised of other materials such as titanium, fused silica, or areinforced rigid polymer material (e.g., a carbon-fiber PEEK™ or othermetal-braided polymer material). More rigid polymer materials may bemore desirable in some applications, since stainless steel has somedrawbacks in biological environments. For example, components in abiological fluid can attach to stainless steel, and stainless steel ionsmay leak into said fluid—both events having the potential to obscuremeasurements in liquid chromatography and other analytic chemistryapplications. The nut 1001 thus can comprise biocompatible materials,such as polyetheretherketone (PEEK), which are generally inert withrespect to biological materials. Those skilled in the art willappreciate that the slot 1050 of the nut 1001 need not run the entirelongitudinal length of the nut 1001. In addition, a plurality of slotscan be provided instead of a single slot 1050. For example, the nut 1001could have a top slot at the top end 1025 of the nut 1001 and also abottom slot at the bottom end 1005 of the nut 1001.

Referring now to FIG. 15, a cross-sectional view of the nut 1001 isshown. Like features in FIGS. 14-16 have the same numerals for ease ofreference. As shown in FIG. 15, the nut 1001 has a passageway 1030extending through the nut 1001 generally along the longitudinal axis ofthe nut 1001. The first end portion 1005, externally threaded portion1010, lower portion 105, knurled portion 1020, and second end 1025correspond to those portions as shown in FIG. 14. As also shown in FIG.15, the nut 1001 has an interior seating portion 1040 proximate towardsthe first end 1005 of the nut 1001, with the interior seating portion1040 open to opening 1028. The interior seating portion 1040 is adaptedto receive and removably hold a tube assembly comprising a tube and aliner sleeve, transfer tube, or other sleeve (not shown in FIG. 15) inplace. For example, any of the sleeves described above, includingwithout limitation the sleeve 12 or sleeve 92, can be adapted to fitwithin the interior seating portion 1040 of the nut 1001. Moreover, theinterior seating portion 1040 at one end has an end portion 1045. Asshown in FIG. 15, the interior seating portion 1040 has a wider diameterthan that of other portions of the passageway 1030 in the nut 1001. Theend portion 1045 provides a seat at one end of the interior seatingportion 1040. When assembled, the seat at the end portion 1045 of nut1001 allows a compressive force to be applied by the end portion 1045against a sleeve held within the interior seating portion 1040 of thenut 1001, such as when the nut 1001 is rotated relative to a port orother component to make up a fluidic connection or fitting assembly,such as described above with respect to other embodiments, therebytransferring the compressive force to the end of the tube assembly as itabuts a face in a port or other component.

Now referring to FIG. 16, a different cross-sectional view of the nut1001 is provided. As with FIG. 15, the numbering in FIG. 16 uses likenumerals to refer to the same features as shown in FIGS. 14 and 15 forconvenience. The longitudinal extension along the length of the nut 1001of the slot 1050 (not labelled in FIG. 16), as well as its radialextension from the passageway 1030 to the exterior surface of the nut1001, becomes apparent with a comparison of FIGS. 15 and 16. Also shownin FIG. 16 is a flared portion 1060 located at the first end of the nut1001. The portion 1060 provides an opening 1028 with a wider diameterthan the interior seating portion 1040, thus allowing a user to moreeasily and quickly insert a tubing assembly (such as a combinationcomprising a tube and a sleeve as described above) into the nut 1001.

It will be appreciated that, as noted below, the tubing, and also thecomponents of a fitting assembly or connection system, used in manyanalytical instrument systems for fluidic connections can be very small.Moreover, the components used in many analytical instrument systems canvary, and often need to be changed or replaced, such as replacingcolumns, pumps, injection valves, and so forth, whether when switchingfrom one particular application of the system for one type of analysisto another or substantially re-organizing the system and its components.Given the small size of the tubing and fitting assembly or fluidicconnection components, such as nuts, ferrules, sleeves, transfer tubing,tips, and so forth, especially together with the complexity of manyanalytical instrument systems, many operators often spend additionaltime and effort locating the tubing for a connection or locating anfitting assembly, sometimes in very awkward or difficult to reachlocations. By providing a slot 1050 in the nut 1001, an operator canmore easily install or disconnect a fluidic connection in an AI system.For example, to make a connection, an operator can first locate orinsert the nut 1001 in a port, and then easily insert a portion of thetubing or tube assembly through the slot 1050 of the nut 1001, and thentighten the nut 1001 in the port to form a sealed connection. Similarly,an operator, when disconnecting a fluidic connection, can simply rotatethe nut 1001 relative to the port to loosen the fitting assembly and,without removing the nut 1001 from the port, remove the tubing bypulling the tubing through the slot 1050.

Those skilled in the art will appreciate that the current disclosureprovides a tubing assembly and a fitting assembly which can be used formaking one or more connections in any system that utilizes a face seal(such as a flat-bottomed port), and can withstand the fluid pressuresrequired for ultra-high pressure liquid chromatography (UHPLC) and otheranalytical instrument applications. While PEEK lined steel (PLS) tubinghas been used in other applications, those skilled in the art willappreciate that the tubing and fitting assembly of the presentdisclosure overcomes issues with the use of PLS, such as, for example,difficulties encountered by users because of the inability of PLS tobend. Those skilled in the art will appreciate that the fitting andtubing assembly configurations described and shown in this disclosurefocus on only one end of the tubing and fitting assembly, but thepresent disclosure may be used in embodiments as a complete fluidicconnection between two components, for example, such as a connectionincluding two nuts and tubing with two ends such as described and shownin this disclosure for providing a fluid connection between any twopoints in an analytical instrument system or other system.

Those skilled in the art will further appreciate that the tubing andfitting assemblies shown and disclosed herein will successfully handlefluid connections in systems in which small volumes of a fluid at highpressures are needed. For example, the tubing in accordance with thepresent disclosure may have an outside diameter (OD) in the range offrom about 1/64 inches to about ¼ inch, or about 1/64, 1/32, 1/16, ⅛ or¼ of an inch in diameter inclusive, and may have an inner diameter (ID)of from about 0.001 to about 0.085 inches, or about 0.001, 0.002, 0.006,0.010, 0.015, 0.020, 0.025, 0.030, 0.060, or 0.085 inches, inclusive.Moreover, the assembly described and shown in this disclosure is capableof UHPLC pressures (>18,000 psi) at finger-tight torque values of 2-3in*lbs, for example. The assemblies are also flexible and capable ofmultiple connection uses prior to failure. It is believed that thefitting assembly of the present disclosure is able to translaterotational torque directly to axial force to generate the seal with aflat-bottom port which will hold at very high pressures like thosenoted. Those skilled in the art will also appreciate that the fittingassembly of the present disclosure does not require any ferrules orother similar sealing mechanisms, is easy to use by an operator, and cangenerate a seal at high pressures with torque levels that do not requireany tools and are easily obtained by most users. Using such a torqueload to make a test connection with a fitting assembly in accordancewith the present disclosure, we were able to obtain a sealed fluidconnection that maintained a seal at fluid pressures higher than 25,000psi before a burst or a leak.

While the present invention has been shown and described in variousembodiments, those skilled in the art will appreciate from the drawingsand the foregoing discussion that various changes, modifications, andvariations may be made without departing from the spirit and scope ofthe invention as set forth in the claims. For example, the shapes,sizes, features, and materials of the fitting assembly, fluidconnection, and/or analytical instrument systems of the presentdisclosure may be changed. Hence, the embodiments shown and described inthe drawings and the above discussion are merely illustrative and do notlimit the scope of the invention as defined in the claims herein. Theembodiments and specific forms, materials, and the like are merelyillustrative and do not limit the scope of the invention or the claimsherein.

What is claimed is:
 1. A fitting assembly for a flat-bottomed portcomprising: a tube comprising an inner tube and an outer tube, whereinthe inner tube has a fluid pathway therethrough, and wherein the tube isadapted to fit in a first passageway extending through a nut having afirst end and a second end, wherein the tube has a first end and asecond end, and wherein at least one of the first end and second end ofsaid tube has a tube seal face end adapted to form a seal in aflat-bottomed port; a cylindrical transfer tube having a secondpassageway therethrough, wherein at least a portion of the tube islocated within the second passageway of the transfer tube and is securedrelative to the transfer tube; a tip adjacent to and in contact with thetube face seal end, wherein at least a portion of one end of the tip isadapted to form a seal in the flat-bottomed port adapted to engage witha portion of the nut, and wherein a portion of the tip is locatedbetween the tube and the transfer tube, and wherein an end portion ofthe transfer tube abuts an end portion of the tip and is adapted toapply an axial load to the end portion of the tip when the nut isengaged in the port.
 2. The fitting assembly according to claim 1,wherein said tip comprises a compressible material and wherein at leastone of said transfer tube and an inside surface of said tip are adaptedto provide an interference fit with said tube.
 3. The fitting assemblyaccording to claim 1, wherein said tube comprises metal, said transfertube comprises metal, and further wherein said transfer tube comprises apocket portion at a terminal end thereof, and wherein a portion of saidtip is adapted to be held in the pocket portion, thereby providing aninterference seal with a portion of said tube.
 4. The fitting assemblyaccording to claim 1 wherein said tube and said tip each comprise abiocompatible material.
 5. The fitting assembly according to claim 1wherein at least one of said tube and said tip comprises at least one ofthe following: polyetheretherketone (PEEK), polyaryletherketone (PAEK),polyetherketoneketone (PEKK), fluorinated ethylene propylene (FEP),ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE),perfluoroalkoxy (PFA, also called perfluoroalkoxyethylene),polychlorotrifluoroethylene (PCTFE), polymer-sheathed fused silica (suchas PEEKSil), fused silica, or silica borite.
 6. The fitting assemblyaccording to claim 1 wherein at least one of said tube, said transfertube, and said tip comprise a material which further comprises a filler.7. The fitting assembly according to claim 6 wherein the fillercomprises fibers.
 8. The fitting assembly according to claim 7 whereinthe filler comprises at least one of carbon fibers, nanofibers, ormetallic fibers.
 9. The fitting assembly according to claim 1 whereineach of the second end of said tube and the end of said tip have asubstantially flat face adapted to provide a seal when pressed againstthe bottom of a flat-bottomed port.
 10. A fitting assembly for aflat-bottomed port comprising: a tube comprising an inner tube and anouter tube, wherein the inner tube has a fluid pathway therethrough,wherein the tube is adapted to fit in a first passageway extendingthrough a nut having a first end and a second end, wherein said tube hasa first end and a second end; a cylindrical transfer tube having asecond passageway therethrough, wherein at least a portion of the tubeis located within the second passageway of the transfer tube and issecured relative to the transfer tube; a tip having a third passagewaytherethrough and providing an interior portion, wherein the tip isadjacent to and in contact with one of the first end and the second endof the tube, wherein the tip is adapted to receive and hold a portion ofone of the first end and the second end of the tube in the interiorportion, wherein at least a portion of one end of the tip is adapted toform a seal in a flat-bottomed port, and wherein a portion of the tip islocated between a portion of the tube and a portion of the transfertube, and an end portion of the transfer tube abuts an end portion ofthe tip and is adapted to supply an axially load thereto.
 11. Thefitting assembly according to claim 10, wherein at least one of saidtransfer tube and a surface of said tip are adapted to provide aninterference fit with said tube.
 12. The fitting assembly according toclaim 10, wherein said transfer tube has a shorter length than said tubeand wherein a portion of said transfer tube is adapted to impinge on aportion of said tip.
 13. The fitting assembly according to claim 10,wherein the tip comprises a metal.
 14. The fitting assembly according toclaim 10, wherein the seal is sufficient to withstand fluidic pressuresin the fluid pathway of at least 10,000 psi.
 15. The fitting assemblyaccording to claim 10, wherein the seal is sufficient to withstandfluidic pressures in the fluid pathway of at least 15,000 psi.
 16. Thefitting assembly according to claim 10, wherein the seal is sufficientto withstand fluidic pressures in the fluid pathway of at least 20,000psi.